Remaining Life Diagnosis Method and Remaining Life Diagnosis Device for Wind Power Generation Equipment

Abstract

To provide a method for diagnosing a remaining service life of a wind power generator, which enables remaining service life evaluation in consideration of dynamic characteristics of the wind power generator by using only information that is easily available by wind power generation companies.SOLUTION: In a method for diagnosing a remaining service life of a wind power generator 1: a fatigue model creation unit 21 models fatigue characteristics of the wind power generator 1 (for example, a fatigue equivalent load acting on the wind power generator); a design fatigue calculation unit 22 calculates design fatigue from the fatigue characteristics and design wind conditions; an actual fatigue calculation unit 23 calculates actual fatigue from the fatigue characteristics and actual wind conditions at a construction site of the wind power generator; and a remaining service life evaluation unit 24 calculates a remaining service life using the design fatigue and the actual fatigue. For example, by modeling the fatigue equivalent load acting on the wind power generator from easily available information, and by quantifying and comparing accumulated fatigue under the design wind conditions and the actual wind conditions from the obtained fatigue equivalent load, and from a wind speed frequency distribution and turbulence intensity under the design wind conditions and the actual wind conditions, the remaining service life is diagnosed with high accuracy.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for diagnosing the remaining life of a wind power generation device.

Background Art

[0002] Due to the increasing interest in the utilization of renewable energy, a global market expansion of wind power generation devices is predicted. As a megawatt-class wind power generation device, a device including a rotor radially attached to a hub that rotates a blade, a nacelle that supports the rotor via a main shaft, and a tower that supports the nacelle while allowing yaw rotation from below is frequently used.

[0003] In a wind power generation device, power generation is performed using wind that changes every moment as an energy source. Therefore, when the wind speed and turbulence of the wind actually flowing into the wind power generation device are weaker than the design conditions, a margin is generated in the fatigue accumulated in the wind power generation device, and it is often possible to operate for a longer period than the design life. Although such life extension is frequently performed, it is necessary to accurately estimate how many years the target wind power generation device can operate in the future when extending the life.

[0004] As a method for estimating the life of a wind power generation device, Patent Document 1 proposes a method of estimating the fatigue damage degree and the remaining life at unmeasured positions by attaching strain sensors to a very small part of the wind power generation device and using the design information of the wind power generation device.

[0005] Patent Document 2 proposes a method of quantifying the degree of fatigue accumulation from the frequency distribution of the fluctuating dynamic pressure in the wind power generation device to be diagnosed and the frequency distribution of the fluctuating dynamic pressure under the design conditions using the fluctuating dynamic pressure, which is the product of the average value and the standard deviation of the wind speed. In addition, the mechanical characteristics are considered by multiplying the fluctuating dynamic pressure by the thrust coefficient of the rotor or the moment coefficient of the blade.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-217133 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-188612 [Summary of the Invention] [Problems to be Solved by the Invention]

[0007] However, the method described in Patent Document 1 requires a strain sensor that is rarely attached to commercial wind power generation devices, and it is difficult to obtain the necessary design information unless one is a wind power generation device manufacturer.

[0008] On the other hand, although the method described in Patent Document 2 is easily applicable, the mechanical characteristics of wind power generation devices that can be considered are limited to the thrust coefficient and the moment coefficient. Therefore, when the mechanical characteristics change significantly according to the wind speed and the turbulence intensity and affect the degree of fatigue accumulation, it may be difficult to accurately estimate the remaining life.

[0009] The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method and an apparatus for diagnosing the remaining life of a wind power generation device that can evaluate the remaining life considering the mechanical characteristics of the wind power generation device using only information that is easily available to wind power generation operators. [Means for Solving the Problems]

[0010] To solve the above problems, a method for diagnosing the remaining life of a wind power generation device according to the present invention is a method for diagnosing the remaining life of a wind power generation device using a remaining life diagnosis device, wherein the remaining life diagnosis device includes a fatigue model creation unit, a design fatigue calculation unit, an actual fatigue calculation unit, and a remaining life evaluation unit. The fatigue model creation unit models the fatigue characteristics of the wind power generation device (for example, the fatigue equivalent load acting on the wind power generation device), the design fatigue calculation unit calculates the design fatigue from the fatigue characteristics and the design wind conditions, the actual fatigue calculation unit calculates the actual fatigue from the fatigue characteristics and the actual wind conditions at the construction site of the wind power generation device, and the remaining life evaluation unit calculates the remaining life using the design fatigue and the actual fatigue. Upon that, the fatigue model creation unit calculates the fatigue equivalent load of the blade using the wind speed and rotational speed measured by the wind power generation device. It is characterized by this. Other aspects of the present invention will be described in the embodiments described later.

Advantages of the Invention

[0011] According to the present invention, it is possible to evaluate the remaining life considering the mechanical characteristics of the wind power generation device using only information that is easily available to wind power generation operators.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Modes for Carrying Out the Invention

[0013] Embodiments for implementing the present invention will be described in detail with reference to the drawings as appropriate. FIG. 1 is an overall schematic configuration diagram of a wind power generation device 1 according to the present embodiment. As shown in FIG. 1, the wind power generation device 1 includes blades 2 that rotate by receiving wind, a hub 3 that supports the blades 2, a nacelle 4, and a tower 5 that rotatably supports the nacelle 4. Inside the nacelle 4, there are provided a main shaft 6 connected to the hub 3 and rotating together with the hub 3, a speed increaser 7 connected to the main shaft 6 for increasing the rotational speed, and a generator 8 that rotates the rotor at a rotational speed increased by the speed increaser 7 to perform power generation operation. The part that transmits the rotational energy of the blades 2 to the generator 8 is called a power transmission part. In the present embodiment, the main shaft 6 and the speed increaser 7 are included in the power transmission part. And the speed increaser 7 and the generator 8 are held on the main frame 9. Also, a rotor 10 is constituted by the blades 2 and the hub 3.

[0014] At the bottom (lower part) inside the tower 5, a power converter 11 for converting the frequency of electric power, a switching switch for opening and closing the current, a transformer (not shown), a control device 12, etc. are arranged. As the control device 12, for example, a control panel or SCADA (Supervisory Control And Data Acquisition) is used.

[0015] Note that the wind power generation device 1 shown in FIG. 1 shows an example in which the rotor 10 is constituted by three blades 2 and the hub 3, but is not limited thereto. The rotor 10 may be constituted by the hub 3 and at least one blade 2.

[0016] FIG. 2 is a diagram showing the configuration of the remaining life diagnosis device 20 according to the present embodiment. FIG. 2 shows the configuration of the remaining life diagnosis device 20 for the blade 2 of the wind power generation device 1 shown in FIG. 1. The remaining life diagnosis device 20 includes a processing unit, an external storage unit, an input unit, a display unit, a communication unit, etc., and the processing unit is provided with a fatigue model creation unit 21, a design fatigue calculation unit 22, an actual fatigue calculation unit 23, and a remaining life evaluation unit 24. The display unit is a display or the like, and displays the execution status and execution results of the processing by the remaining life diagnosis device 20. The input unit is a device for inputting instructions to a computer such as a keyboard or a mouse, and inputs instructions such as program startup. The processing unit is a central processing unit (CPU), and executes various programs stored in the memory. The communication unit exchanges various data and commands with other devices via a LAN or the like. The external storage unit stores various data for the remaining life diagnosis device 20 to execute processing. The memory holds various programs and temporary data for the remaining life diagnosis device 20 to execute processing.

[0017] (Fatigue model creation unit 21) In the fatigue model creation unit 21, the shape of the blade 2 and the operating conditions of the wind power generation device 1 are estimated using the catalog of the wind power generation device, the monitoring device, the construction drawings, and known theoretical formulas, etc., and the fatigue equivalent loads in the in-plane direction and out-of-plane direction acting on the blade 2 are calculated using numerical simulation.

[0018] FIG. 3 is a diagram for explaining the in-plane direction and out-of-plane direction of the blade 2. The definitions of the in-plane direction and out-of-plane direction are illustrated in FIG. 3. Reference numeral 100 is a rear view of the nacelle 4 as viewed from the rear, and in this rear view 100, the rotation direction of the blade 2 (see the broken line) is taken as the in-plane direction. On the other hand, reference numeral 110 is a side view of the nacelle 4 as viewed from the side, and in this side view 110, the front-rear direction of the blade 2 (see the broken line) is taken as the out-of-plane direction.

[0019] Returning to FIG. 2, the processing within the fatigue model creation unit 21 differs for each diagnosis target. In the embodiment, the loads in the in-plane direction and out-of-plane direction of the blade 2 are targeted, but this is not limiting, and the diagnosis target may also be a component of the wind power generation device 1 other than the blade 2. Examples of components other than the blade include the tower 5, the main shaft 6, the speed increaser 7, the generator 8, the main frame 9, etc., which can be the diagnosis targets.

[0020] FIG. 4 is a diagram for explaining a method of calculating the in-plane fatigue equivalent load of a blade. FIG. 4 shows one method for modeling the in-plane fatigue equivalent load. First, from the typical blade density distribution mode 401 and the rotor radius 402, a density distribution estimation formula 403 represented by the following (Equation 1) is constructed.

[0021]

Equation

[0022] Here, r n is the dimensionless length with the root of the blade as 0 and the tip as 1, m(r n ) is the density distribution per unit length in the longitudinal direction of the blade, Φ(r n ) is the density distribution mode 401, R is the rotor radius 402 or the blade length, and A and B are unknown correction coefficients.

[0023] As a result of the inventors' intensive studies, it was revealed that the value obtained by dividing the density distributions m(r n ) of various blades by the 1.3 power of the rotor radius 402 (R) has approximately the same distribution Φ(r n ). Therefore, the density distribution can be calculated inversely from this Φ(r n ) and R. However, if Φ(r n ) is used as it is, the blade mass 404 and the blade center of gravity 405 may differ from the actual object. Therefore, the correction coefficients A and B are used to match the blade mass 404 and the blade center of gravity 405 with the actual object.

[0024] In (Equation 1), the 1.3rd power of the rotor radius 402 (R) is used, but it is not necessarily required to be the 1.3rd power. In the past, there was a literature suggesting that the 1.5th power is good, and with the future weight reduction of the blade, a value smaller than the 1.3rd power may also be reasonable. Φ(r n ) can be easily obtained by dividing the generally published density distribution of the blade by the 1.3rd power of R.

[0025] Figure 5 is a diagram for explaining an example of the density distribution mode of the blade. In Figure 5, the horizontal axis is the dimensionless length with the blade root being 0 and the tip being 1, and the vertical axis is the density distribution mode. The shape of blade 2 is shown above Figure 5. The density distribution of blade 2 (the density distribution mode of the blade) is, for example, the density distribution as shown in Figure 5.

[0026] The correction coefficients A and B in Equation 1 are determined by solving the following simultaneous equations 406 regarding the blade mass 404 (M) and the blade center of gravity 405 (CG).

[0027]

Equation

[0028]

Equation

[0029] Here, r is the distance from the root of the blade, and R B is the blade length obtained by subtracting the hub radius from the rotor radius R. Since (Equation 2) and (Equation 3) contain the correction coefficients A and B which are unknown variables, by solving these equations simultaneously, the values of the correction coefficients A and B are uniquely determined. Substituting the obtained correction coefficients A and B into Equation 1, we return to Figure 4 and can estimate the blade density 407. Once the blade density 407 is known, the blade bending moment distribution 408 can be calculated.

[0030] FIG. 6 is a diagram for explaining the bending moment distribution of blade 2. In FIG. 6, the horizontal axis represents the dimensionless length with the root of the blade being 0 and the tip being 1, and the vertical axis represents the bending moment distribution. Above FIG. 6, the shape of blade 2 is shown. When blade 2 as shown in FIG. 6 is in the horizontal direction, the blade bending moment distribution 408 (see FIG. 4) due to its own weight can be calculated, and this can be used as the weighted amplitude for calculating the in-plane blade fatigue equivalent load 411 (see FIG. 4).

[0031] Note that in the in-plane direction, since the blade bending moment due to its own weight when the blade is exactly sideways corresponds to the maximum amplitude of the moment acting on the blade, if only this moment due to its own weight is considered, the fatigue equivalent load can be estimated with high accuracy.

[0032] On the other hand, referring back to FIG. 4, for the calculation of the in-plane blade fatigue equivalent load 411, the rotor rotation speed (rotation speed characteristic 410) for each operating wind speed of the wind power generation device is required. This can be estimated from the information 409 of the wind speed and rotation speed included in the SCADA data using the least squares method or the like.

[0033] From the blade bending moment distribution 408 and the rotation speed characteristic 410 obtained in this way, the in-plane blade fatigue equivalent load 411 at an arbitrary wind speed at an arbitrary longitudinal position of the blade can be calculated.

[0034] FIG. 7 is a diagram for explaining the fatigue equivalent load in the in-plane direction of the blade. The horizontal axis is the average wind speed, and the vertical axis is the fatigue equivalent load in the in-plane direction. For example, when calculating the in-plane blade fatigue equivalent load 411 (see FIG. 4) at the blade root as shown in FIG. 7, the value at the root is selected from the blade bending moment distribution 408 (see FIG. 4), raised to the power of the slope of the SN curve of the blade material, and multiplied by the rotation speed obtained from the rotation speed characteristic 410 (see FIG. 4), then the fatigue equivalent load can be obtained.

[0035] However, returning to FIG. 4, the in-plane blade fatigue equivalent load 411 obtained is due to the self-weight of the blade, and since the effects such as blade vibration are not considered, a correction factor may be introduced as necessary. Alternatively, in order to be able to consider vibration, when calculating the out-of-plane fatigue equivalent load described later, the blade shape, density distribution, rotational speed characteristics, and pitch angle characteristics obtained in the same way as the rotational speed characteristics are used for numerical simulation to calculate the in-plane blade fatigue equivalent load 411.

[0036] FIG. 8 is a diagram for explaining a method of calculating the out-of-plane fatigue equivalent load of blade 2. FIG. 8 shows one method for modeling the out-of-plane fatigue equivalent load. First, the blade shape 801 is obtained from a photograph, drawing, etc., and the chord length distribution 802 is obtained based on known blade length, root diameter, etc. When using a photograph, for example, when the wind power generation device 1 is stopped and the blade 2 is in the feathered state where it is not affected by the wind, and the blade 2 is facing directly downward, the blade 2 is photographed from the direction directly beside the nacelle 4 as shown in FIG. 1, and a proper shape can be obtained.

[0037] FIG. 9 is a diagram for explaining how to obtain the optimal tip speed ratio. The horizontal axis represents the average wind speed, and the vertical axis represents the rotor rotational speed. From the wind speed and rotational speed included in the SCADA 409 data, the gradient in the range where the rotor rotational speed changes with respect to the wind speed as shown in FIG. 9 is calculated by the least squares method or the like, and by dividing by the rotor radius, the tip speed ratio 803 (TSR: Tip Speed Ratio) is obtained. When the tip speed ratio 803 is known, for example, the twist angle distribution 804 of blade 2 when maximizing the power generation amount can be obtained by the following theoretical formula.

[0038]

Equation

[0039] Here, θ(r) is the twist angle, and α(r) represents the angle of attack, which is the angle between the resultant velocity vector composed of the wind speed and the rotational speed and the chord length direction. The angle of attack varies depending on the airfoil that constitutes the cross-section of blade 2. In wind power generation device 1, the angle of attack at the maximum lift-drag ratio of the airfoil is often used. For example, values such as 8 degrees on the inner side and 4 degrees on the outer side than the position where the chord length of blade 2 is maximum may be used.

[0040] (Equation 4) is an example of giving each twist distribution. In recent years, since blade 2 may be designed for minimizing the power generation cost rather than maximizing the power generation amount, another equation may be used.

[0041] Finally, as also described for the in-plane fatigue equivalent load, the rotational speed - pitch angle characteristic 806 is estimated from the information on the wind speed, rotational speed, and pitch angle included in the data of SCADA 805 using linear regression by the least squares method, moving average, etc.

[0042] FIG. 10 is a diagram for explaining the rotational speed and pitch angle characteristics. Regarding FIG. 10, the diagram with reference numeral 200 is the rotational speed characteristic diagram 200 when the horizontal axis is the wind speed and the vertical axis is the rotor rotational speed. On the other hand, the diagram with reference numeral 210 is the pitch angle characteristic diagram 210 when the horizontal axis is the wind speed and the vertical axis is the pitch angle. The rotational speed - pitch angle characteristic 806 as shown in FIG. 10 can be estimated from the rotational speed characteristic diagram 200 and the pitch angle characteristic diagram 210 in FIG. 10.

[0043] Using this information, the fluid force acting on blade 2 can be calculated by simulation using blade element momentum theory or computational fluid dynamics, and the out-of-plane blade fatigue equivalent load 807 can be calculated.

[0044] FIG. 11 is a diagram for explaining the change in the out-of-plane fatigue equivalent load of blade 2 due to the turbulence intensity. The horizontal axis is the mean wind speed, and the vertical axis is the out-of-plane fatigue equivalent load. Since the out-of-plane fatigue equivalent load varies greatly depending on the turbulence intensity, it is desirable to perform simulations for various turbulence intensities and calculate the fatigue equivalent load for each turbulence intensity as shown in FIG. 11.

[0045] If the blade density distribution 407 (see FIG. 4) can be estimated, in addition to the calculation of the fluid force, an aeroelastic calculation can be applied, and the influence of the vibration of blade 2 can be reflected in the in-plane and out-of-plane fatigue equivalent loads. Alternatively, the out-of-plane blade fatigue equivalent load 807 (see FIG. 8) can also be calculated by a simple method. For example, using the blade element momentum theory, the fluid force when blade 2 is located directly above and below nacelle 4 is calculated, the bending moment distribution is obtained, and the load amplitude calculated as the difference in the bending moments when directly above and below is raised to the power of the slope of the SN curve of the blade material and multiplied by the rotational speed, then the out-of-plane blade fatigue equivalent load 807 (see FIG. 8) can be obtained.

[0046] (Design fatigue calculation unit 22) As described above, using the fatigue equivalent load obtained by the fatigue model creation unit 21 and the design wind conditions, the design fatigue calculation unit 22 calculates the fatigue accumulation under the design wind conditions. The design wind conditions are determined in the type certification of the wind power generation device and are generally defined by the annual average wind speed and the turbulence class.

[0047] FIG. 12 is a diagram for explaining the wind speed frequency distribution under the design wind conditions and the actual wind conditions. The horizontal axis is the average wind speed, and the vertical axis is the wind speed frequency distribution. FIG. 12 shows an example of the wind speed frequency distribution, and it is preferable to use the actual wind conditions, but the measurement data is not necessarily the same every year. Therefore, the design fatigue calculation unit 22 calculates the fatigue accumulation under the design wind conditions. On the other hand, the actual fatigue calculation unit 23 described later calculates the fatigue accumulation under the actual wind conditions at the construction site of the wind power generation device 1.

[0048] First, when the influence of turbulence intensity on the fatigue equivalent load is not considered, the fatigue equivalent load is corrected using the turbulence class. Specifically, when numerical simulation is not used in the in-plane direction calculation or a simple method is used in the out-of-plane direction calculation in the above-mentioned fatigue equivalent load calculation method, correction may be performed. However, since the influence of turbulence in the in-plane direction is small, it may be ignored. As a correction method, for example, it is conceivable to use the parameter that defines the turbulence class. The turbulence class is defined by I in the following (Equation 5).

[0049]

Number

[0050] Here, U is the wind speed, and TI is the 90% tile value of the turbulence intensity. For the correction, the value of I specified as the design wind condition may be used to multiply the fatigue equivalent load by the correction value defined as a function of I. For example, according to the magnitude of the turbulence intensity, for the cases where the values of I are 0.16, 0.14, and 0.12, the corrected fatigue equivalent load as shown in Figure 11 is calculated. Using the corrected fatigue equivalent load obtained in this way and the wind speed frequency distribution of the Rayleigh distribution determined by the annual average wind speed as shown in Figure 12, D factor is used to quantify the design fatigue.

[0051]

Number

[0052] Here, U in and U out represent the cut-in and cut-out wind speeds that are the minimum and maximum wind speeds at which the wind power generation device 1 generates electricity, φ(U) is the occurrence frequency of the wind speed, DEL′(U) is the corrected fatigue equivalent load, and m is the slope of the SN curve of the blade material. In the calculation of the design fatigue, it is advisable to use the wind speed frequency distribution that follows the Rayleigh distribution defined by the annual average wind speed of the design wind condition for φ(U). At this time, φ(U) is determined so that the integral value of φ(U) becomes the design life of the wind power generation device 1.

[0053] (Actual fatigue calculation unit 23) In the actual fatigue calculation unit 23, D under the actual wind conditions at the construction site of the wind power generation device 1 is calculated as the actual fatigue using (Equation 6). First, similar to the design fatigue calculation unit 22, correction is applied to the fatigue equivalent load as necessary. At this time, for the parameter I of the turbulence class used for the correction, the 90% tile value of the turbulence intensity at each wind speed is calculated using the wind speed and turbulence intensity of the SCADA data representing the actual wind conditions, and it is determined using the least squares method or the like so that (Equation 5) is closest to the obtained curve. Next, the wind speed frequency distribution φ(U) under the actual wind conditions as shown in FIG. 12 is obtained from the SCADA data, and D representing the fatigue accumulation under the actual wind conditions is calculated using Equation 6. factor factor is calculated.

[0054] (Remaining life evaluation unit 24) Finally, in the remaining life evaluation unit 24, the remaining life is calculated from D (Dd) under the design wind conditions and D (Dr) under the actual wind conditions calculated by the design fatigue calculation unit 22 and the actual fatigue calculation unit 23. Let the operation period of the wind power generation device 1 to be diagnosed so far be T0, and the acquisition period of the SCADA data that is the basis of the wind speed frequency distribution used when calculating Dr be T1. Then, the remaining life L of the blade 2 of the wind power generation device 1 can be calculated by the following (Equation 7). factor (Dd) and D under the actual wind conditions factor (Dr).

[0055] L = T1 / (Dr / Dd) - T0 ··· (Equation 7)

[0056] Also, the current fatigue damage degree D of the blade 2 of the wind power generation device 1 is D = (Dr × T0) / (Dd × T1) ··· (Equation 8) When T0 = T1, the ratio Dr / Dd of Dr and Dd becomes the fatigue damage degree. When calculating the fatigue equivalent loads in both the out-of-plane direction and the in-plane direction, D in (Equation 6) factor ​Calculate L in both (Equation 7), and consider the smaller value of L calculated for the out-of-plane direction and the in-plane direction as the remaining life of Blade 2. Similarly, when the fatigue equivalent load is calculated for a plurality of components including components other than Blade 2, the minimum value of L calculated for each may be considered as the remaining life of the wind power generation device 1.

[0057] The method for diagnosing the remaining life of the wind power generation device 1 according to this embodiment is a method for diagnosing the remaining life of a wind power generation device using the remaining life diagnosis device 20. The remaining life diagnosis device 20 includes a fatigue model creation unit 21, a design fatigue calculation unit 22, an actual fatigue calculation unit 23, and a remaining life evaluation unit 24. The fatigue model creation unit 21 models the fatigue characteristics of the wind power generation device 1 (for example, the fatigue equivalent load acting on the wind power generation device). The design fatigue calculation unit 22 calculates the design fatigue from the fatigue characteristics and the design wind conditions. The actual fatigue calculation unit 23 calculates the actual fatigue from the fatigue characteristics and the actual wind conditions at the construction site of the wind power generation device. The remaining life evaluation unit 24 is characterized by calculating the remaining life using the design fatigue and the actual fatigue. For example, by modeling the fatigue equivalent load acting on the wind power generation device from easily available information, and quantifying and comparing the fatigue accumulation in the design wind conditions and the actual wind conditions from the obtained fatigue equivalent load, the wind speed frequency distribution, and the turbulence intensity in the design wind conditions and the actual wind conditions, the remaining life can be diagnosed with high accuracy.

[0058] By using the remaining life diagnosis device 20 of the wind power generation device 1 having the above configuration, according to the embodiment, the remaining life of the blade can be diagnosed from easily available information. In this embodiment, the fatigue equivalent load is calculated in consideration of the mechanical characteristics of the blade that vary greatly with the wind speed and the turbulence intensity, and the fatigue accumulation is evaluated using the fatigue equivalent load and the occurrence frequency of the wind speed and the turbulence intensity, enabling highly accurate remaining life diagnosis. On the other hand, in the method of Patent Document 2 described above, since the fatigue accumulation is calculated by multiplying the fluctuating dynamic pressure, which is the product of the average value and the standard deviation of the wind speed, by the thrust coefficient or the moment coefficient representing the mechanical characteristics at the average wind speed, there is a possibility that the changes in the thrust coefficient and the moment coefficient that vary within the range of the standard deviation of the wind speed corresponding to the turbulence cannot be considered.

Explanation of Reference Numerals

[0059] 1 Wind power generation device 2 Blades 3 Hub 4 Nacelle 5 Tower 6 Main shaft 7 Speed increaser 8 Generator 9 Main frame 10 Rotor 11 Power converter 12 Control device 20 Remaining life diagnosis device 21 Fatigue model creation unit 22 Design fatigue calculation unit 23 Actual fatigue calculation unit 24 Remaining life evaluation unit 401 Density distribution mode 402 Rotor radius 403 Density distribution estimation formula 404 Blade mass 405 Blade center of gravity 406 Simultaneous equations of mass and center of gravity 407 Blade density distribution 408 Blade bending moment distribution 409 SCADA (wind speed, rotational speed) 410 Rotational speed characteristics 411 In-plane blade fatigue equivalent load 801 Blade shape 802 Chord length distribution 803 Tip speed ratio 804 Twist angle distribution 805 SCADA (wind speed, pitch angle) 806 Rotational speed - pitch angle characteristics 807 Out-of-plane blade fatigue equivalent load

Claims

1. A method for diagnosing the remaining life of a wind power generation device using a remaining life diagnosis device, wherein the remaining life diagnosis device includes a fatigue model creation unit, a design fatigue calculation unit, an actual fatigue calculation unit, and a remaining life evaluation unit, the fatigue model creation unit models the fatigue characteristics of the wind power generation device, the design fatigue calculation unit calculates design fatigue from the fatigue characteristics and the design wind conditions, the actual fatigue calculation unit calculates actual fatigue from the fatigue characteristics and the actual wind conditions at the construction site of the wind power generation device, when the remaining life evaluation unit calculates the remaining life using the design fatigue and the actual fatigue, the fatigue model creation unit calculates the fatigue equivalent load of the blade using the wind speed and rotational speed measured by the wind power generation device A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

2. In the method for diagnosing the remaining life of a wind power generation device according to Claim 1, the design wind conditions used in the design fatigue calculation unit are defined by the annual average wind speed and the turbulence class A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

3. In the method for diagnosing the remaining life of a wind power generation device according to Claim 2, the actual wind conditions used in the actual fatigue calculation unit are the wind speed and turbulence intensity measured by the wind power generation device A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

4. In the method for diagnosing the remaining life of a wind power generation device according to Claim 1, the remaining life evaluation unit calculates the remaining life using the fatigue damage degree obtained by dividing the actual fatigue by the design fatigue A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

5. In the method for diagnosing the remaining life of a wind power generation device according to Claim 1, the fatigue model creation unit calculates the fatigue equivalent load of the blade in the in-plane direction of the rotor from the rotor diameter, blade mass, and blade center of gravity of the wind power generation device A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

6. In the method for diagnosing the remaining life of a wind power generation device according to Claim 1, the fatigue model creation unit calculates the fatigue equivalent load of the blade in the out-of-plane direction of the rotor from the theoretical formula of the blade shape and the twist angle of the wind power generation device A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

7. In the method for diagnosing the remaining life of a wind power generation device according to Claim 6, in the theoretical formula of the twist angle used by the fatigue model creation unit, the optimum tip speed ratio calculated from the relationship between the wind speed and rotational speed measured by the wind power generation device is used A method for diagnosing the remaining life of a wind power generation device, characterized by the above.

8. In the method for diagnosing the remaining life of a wind power generation device according to claim 6, the blade shape used in the fatigue model creation unit uses a photograph of the blade A method for diagnosing the remaining life of a wind power generation device, characterized by this.

9. In the method for diagnosing the remaining life of a wind power generation device according to claim 1, the fatigue model creation unit estimates the shape of the blade and the operating conditions of the wind power generation device, and calculates the fatigue equivalent loads in the in-plane direction and out-of-plane direction acting on the blade using numerical simulation A method for diagnosing the remaining life of a wind power generation device, characterized by this.

10. A fatigue model creation unit that models the fatigue characteristics of a wind power generation device; A design fatigue calculation unit that calculates design fatigue from the fatigue characteristics and the design wind conditions; An actual fatigue calculation unit that calculates actual fatigue from the fatigue characteristics and the actual wind conditions at the construction site of the wind power generation device; A remaining life evaluation unit that calculates the remaining life using the design fatigue and the actual fatigue, and the fatigue model creation unit calculates the fatigue equivalent load of the blade using the wind speed and the rotational speed measured by the wind power generation device A device for diagnosing the remaining life of a wind power generation device, characterized by this.

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